With the progress of flexible display technology, the manufacture of a high-caliber flexible display has become a focus for display panel manufacturers and research/design institutions. The structure of the flexible display panel is different from a glass-based display panel in that the flexible display panel uses an organic material to form the substrate. During the manufacturing process of the substrate of the flexible display panel, the liquid organic substance have to be dispensed and cured so as to form the substrate. As the organic substance in the liquid form is prone to induce bubbles, the cured substrate may contain a large number of bubbles. These bubbles will expand in the subsequent process under vacuum and hot environment. In the end, bubbles having a diameter of millimeters may come into being. The existence of these bubbles may severely affect the display performance of the flexible display panel.